iOS 11.2.1 (build 15C153) is an official Apple over-the-air update for the iPhone 7 (GSM), released on 2017-12-13T18:14:53Z. The update package is 1.19 GB. This is a delta (partial) update that requires 10.2.1 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: a288c675eaf462ab002de9f8b5cb6e9b6af2cf68.zip.